Two inventive Physics and Computer Science students at the National University of Lesotho (NUL) have designed a device that allows people to see their heartbeat – and it costs less than M200.
Tobatsi Mohlalanyane and Itumeleng Mothibeli say their creation is more than a class project. It is an affordable, portable tool designed to bridge healthcare gaps in communities where distance and cost often block access to essential medical equipment.
“We wanted something that could be useful beyond the classroom. That’s why we kept it simple, cheap, and easy to repair with parts that anyone can find locally,” Mohlalanyane said recently.
The principle behind the gadget is straightforward. Every heartbeat pushes a wave of blood through the body. By clipping the device onto a person’s earlobe – chosen for its thin skin and convenient location – a red light is shone through the tissue.
A light sensor then measures how much light passes through. When the heart pumps and more blood flows, less light passes; when the heart rests, more light passes. The sensor picks up these subtle changes and makes a small LED blink in rhythm with the heartbeat.
“Suddenly, you’re watching your heart talk to you in Morse code,” Mohlalanyane explained.
Unlike digital monitors, this device is purely analogue. There is no software, no coding, and no need for expensive components. This simplicity, the students argue, makes it both affordable and easy to maintain, especially in rural areas.
During initial testing with five volunteers, the students evaluated the device both at rest and after exercise. The results were encouraging.
“The light blinked almost perfectly in sync with their actual pulses. At rest, the readings were within about three beats per minute of the true heart rate. That’s a strong result for a device this basic,” noted Mothibeli.
Still, the project was not without challenges. Movement made the readings less accurate, and bright ambient light interfered with the sensor. The students tackled this by designing a small cover that shields the sensor, greatly improving performance.
The pair believe their gadget could one day become a vital tool for village health workers in Lesotho and beyond. Instead of expensive monitors, health workers could use these low-cost devices to detect irregularities in heart activity early, giving patients a better chance of timely treatment.
“Our long-term goal is to add features like automatic heart rate calculation, improved accuracy in bright conditions, and smartphone connectivity,” indicated Mohlalanyane.
Mothibeli added: “If community health workers can carry these into villages, it could change the way we detect and respond to heart problems in rural areas.”
The students stress that the project has been more than just an academic exercise. It has taught them about persistence, practical problem-solving, and the gap between theory and real-world application.
“Theory is just the starting point. What looks good on paper doesn’t always work in practice. But if you keep experimenting and refining, you can create something that actually makes a difference,” pointed out Mohlalanyane.
In a country where health systems are stretched and many people live far from hospitals, innovations like this show the potential of student ingenuity to tackle real-world problems. For less than the cost of a trip to town, a villager could soon have access to a tool that helps monitor one of the most vital signs of life: the heartbeat.
Mohlalanyane and Mothibeli’s device is still in its early stages, but its promise is clear: with creativity, persistence, and a focus on accessibility, even modest resources can produce life-saving solutions.
